The present invention relates to industrial process transmitters, and more particularly to housing assemblies for industrial process transmitters and methods of making the same.
Industrial process transmitters are used to sense, measure, manage and control processes in industrial processing facilities. Typically, industrial process transmitters include a housing that is sealed and explosion-proof. The geometry of these housings, both internal and external, can be relatively complex. In the prior art, these housings were generally one-piece die-castings made from aluminum, which is a material well-suited for die casting. Additional machining was then performed on the die-casting, as desired, and the casting was painted. However, aluminum is a relatively reactive material, making it less desirable for certain applications were the housing is exposed to materials that are reactive, caustic, etc. Paints and similar coatings may be undesired or inadequate for protecting the aluminum material of the housing in certain applications. Other materials, like stainless steel, are not readily able to be die cast, but instead require a process like investment casting, which is a relatively complicated and expensive process as compared to die casting. Furthermore, casting processes tend to leave relatively rough surfaces (greater than about 125 Ra), which are undesirable for hygienic applications where rigorous cleaning or sterilization processes must be performed. Machining all surfaces of a casting to increase smoothness would be an undesirably time-consuming and expensive undertaking.
Thus, an alternative industrial process transmitter housing assembly is desired.